Influence of geometrical parameters on flow hydraulic properties in inclined weirs

Weirs are one of the most important hydraulic structures for flow control, water measurement, and regulating of upstream water elevation in canals, irrigation networks, and rivers. For a given channel width, inclined weirs have a longer effective length in comparison with the usual rectangular sharp-crested weirs, and this could be effective on their discharge coefficients and efficiency. In the present study, the effect of the geometrical parameters on the hydraulic properties of the flow in inclined weirs was investigated using 3D Ansys Fluent software. Numerical simulations were validated by laboratory results. Weir height (P), weir angle with channel wall (α), water height above the weir (H), and effective length (Le) were investigated. The MR-linear regression model performance in applying the inclined weir discharge coefficient was investigated. The results indicated that this relation is very similar to the numerical model results. The numerical model results were also compared with those of the other researchers. Inclined weirs discharge coefficient at different effective lengths decreases by increasing H/P, and at a constant H/P, by increasing the weir effective length, the discharge coefficient decreases, and the flow rate increases. Increasing in weir height results increasing in discharge.